My Vista 64 installation has drive C, a 150 GB hard drive. I also has a 1.5 TB drive D. My C drive has 12.3 GB free. I don't know what's using up all the space. There's almost 83 GB unaccounted for!!!

As per this question and this question, I downloaded WinDirStat and SpaceMonger. WinDirStat, once I found the right options, tells me there's 82.9 GB of . SpaceMonger, which has a particularly nice display of the data, tells me there's 82.3 GB "Unscanned", with 2 unscannable folders.

Where do I turn now? Both tools roughly agree there's a large amount of data on my drive, but neither seem to be able to tell me what.

I've tried the standard approach; disk cleanup, remove hibernation file, set the virtual memory to the D drive instead of the C drive.

4 Answers
4

It could be the System Restore service (and previous versions) eating that space up. Those are stored in the hidden \System Volume Information folder in the root of the drive. If you open an administrative command prompt window you can view the usage of System Restore/Previous versions by issuing and reading the following command

You hit the answer right on the nose! Presumably this is caused by my use of the excellent Rebit backup software, though this is a very nasty side-effect. Thank you.
–
ChrisInEdmontonAug 14 '09 at 2:29

Joshua's answer solved my very similar problem, and I haven't used Rebit.
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Tommy HerbertAug 19 '09 at 20:06